Bulbholders

ABSTRACT

A bulbholder comprises a cylindrical body open at both ends and formed integrally with a lamp reflector. The body is formed internally with recesses to receive, in bayonet fashion, a bulb. A compression spring locates the bulb in the recess and is supported in the body thereof, in one embodiment, by a hooked extension of the spring which engages with a rim formed in the body adjacent the bulb receiving end thereof. In another embodiment, the extension of the spring is secured to the body by a rivet which also secures an electrical terminal thereto.

United States Patent [1 1 Joiner et a1.

1 1 BULBHOLDERS [75] Inventors: John Richard Lincoln Joiner, Sutton Coldfield; Alan John Covel, Solihull, both of England [73] Assignee: The Lucas Electrical Company Limited, Birmingham, England [22] Filed: Dec. 12, 1973 [21] Appl. No.: 424,002

[30] Foreign Application Priority Data Dec. 12, 1972 United Kingdom 57180/72 [52] U.S. Cl 240/143; 240/153; 339/64 R; 339/88 R; 339/90 F; 339/252 R [51] Int. Cl. l-l0lr 13/16 [58] Field of Search 240/142, 143, 153; 339/64 R, 88 R, 90 F, 176 L, 219 R, 220 L,

[56] References Cited UNITED STATES PATENTS 900,426 10/1908 Rucker 240/142 [4 1 May 13, 1975 959,205 5/1910 DOlier, .lr. 240/142 2,443,743 6/1948 3,040,285 6/1962 3,206,708 9/1965 3,569,907 3/1971 3,718,892 2/1973 Burgess et a1 339/88 R X FOREIGN PATENTS OR APPLICATIONS 1,226,486 2/1960 France 339/90 R Primary Examiner-Joseph F. Peters, Jr.

[57] ABSTRACT A bulbholder comprises a cylindrical body open at both ends and formed integrally with a lamp reflector. The body is formed internally with recesses to receive, in bayonet fashion, a bulb. A compression spring 10- cates the bulb in the recess and is supported in the body thereof, in one embodiment, by a hooked extension of the spring which engages with a rim formed in the body adjacent the bulb receiving end thereof. In another embodiment, the extension of the spring is secured to the body by a rivet which also secures an electrical terminal thereto.

7 Claims, 2 Drawing Figures BULBHOLDERS This invention relates to bulbholders and is more particularly concerned with bulbholders of the bayonet type.

It has previously been the practice to form a bulbholder of bayonet type by means of a moulding, pressing or die-casting operation in which a core of the moulding or die-casting tool is withdrawn from that end of the bulbholder body into which the bulb is inserted in use. Such an operation has had the disadvantage that, in order to form the necessary recesses and shoulders in the bulbholder body, it has been necessary either to form the body using a multi-part core or to form the recesses and shoulders in the body by the use of projecting portions in part of the tool which defines the outer surface of the bulbholder body. In the first case, the tool is complicated and requires constant maintenance and, in the second case, a bulbholder body is provided which has apertures therethrough so that sealing problems to prevent ingress of dirt and moisture are encountered during use of the bulbholder. In both of the above mentioned ways of producing the body, the withdrawal of the core from that end of the tubular body into which the bulb is inserted in use, necessitates the production of a body which tapers outwardly towards that end of the body in order to enable removal of the core. This outward tapering of the body means that the body cannot be made to be a close fit around the bulb with result that the filament of the bulb is not always consistently positioned relative to the bulbholder. This latter consideration is important where the bulbholder is employed to locate the bulb relative to a dished reflector where it is necessary to position the filament accurately relative to the reflector.

It is an object of the present invention to obviate or mitigate the above disadvantages.

According to the present invention there is provided a bulbholder comprising a tubular body open at both ends, opposed recesses and shoulders in said body for receiving in bayonet fashion a bulb when passed into the body via one of the open ends thereof, resilient means disposed in said body and arranged to urge the bulb, in use, against said shoulders, and stop means for preventing resilient means from passing through the other open end of the body.

The stop means may comprise a bar extending transversely of the body adjacent to said other end thereof to be located in opposed apertures in the body, but preferably comprises at least one extension of a compression spring forming the resilient means.

The or each extension may include an outwardly turned end portion of the spring adjacent the said other open end of the body, the or each said outwardly turned end portion being engaged in a recess or aperture in the body adjacent the said open end thereof. However, it is preferred that the or each turned back end portion terminates in an outwardly directed hook, said turned back end portion extending from the end of the spring adjacent the said other open end of the body in a direction towards the said one open end so that the hook engages a rim of the body around said one end thereof.

The bulbholder according to the present invention, because it has a tubular body which is open at both ends, can be produced using a core of a moulding or casting tool which is withdrawn from the said other open end of the body ie that end opposite to which the bulb is inserted in use. This means that a body is produced which tapers inwardly towards the end receiving the bulb in use, whereby the bulb can be accurately located relative to the bulbholder. Furthermore, the removal of the core from the said other end enables the tool to be manufactured in one piece with projections thereon to define the opposed recesses and shoulders.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a longitudinal sectional view of a bulbholder according to the present invention, and

FIG. 2 is a longitudinal sectional view of another type of bulbholder also according to the present invention.

Referring to the drawings, the bulbholder is formed integrally with a reflector 1 (FIG. 1) (only partly shown) in a die-casting operation. The bulbholder comprises a tubular body 2 integrally united with the reflector l by means of an intermediate, generally frus to-conical shell 3. The tubular body 2 is open at both ends 4 and 5 thereof and is formed with a pair of diametrically opposed recesses 6 (only one shown) and a pair of diametrically opposed shoulders 7 (only one shown) therein so that the body can receive, in bayonet fashion, the body of a bulb 8 when inserted into the open end 4 of the body 2 so that diametrically opposed pins 9 on the body of the bulb 8 pass along the recesses 6 and engage the shoulders 7. A recess 10 is formed externally of a rim 11 around the open end 4 of the body 2.

Internally of the body 2 there is carried a centre contact 12 for the bulb 8 and a compression spring 13 lodged between the centre contact 12 and the open end 5 of the body 2. The end of the compression spring 13 adjacent the open end 5 has an integral turned back extension 14 which extends longitudinally of the body 2 away from the open end 5 and towards the open end 4 to terminate in a hook 15 which engages with the rim 11 in the vicinity of the recess 10. In this manner, the compression spring 13 is held against passage through the open end 5 of the body 2. The compression spring 13 serves to urge the pins 9 on the bulb 8 against the shoulders 7 so as to retain the bulb 8 firmly within the tubular body 2.

Provision of the open end 5 of the body 2, the latter can be die-cast using a tool core which is withdrawable from the open end 5 rather than from the open end 4 as has previously been the case. This design permits the construction of the core to be considerably simplified due to the fact that it can be manufactured in a single piece. Furthermore, the body so produced does not have any apertures in the side walls thereof so that sealing can be effected merely by a rubber end cap over the end 5. Furthermore, the tool core withdrawal from the open end 5 means that the body 2 tapers inwardly towards the open end 4 thereof thus ensuring that the bulb 8 is accurately located within the body 2 since rocking of the bulb 8 about its pins 9 is limited due to tapering nature of the body 2 at the open end 4.

Referring now to FIG. 2 of the drawings, the bulbholder illustrated therein is similar to the bulbholder of FIG. 1 and similar parts are accorded the same reference numerals, primed.

In this embodiment, the assembly of reflector l' and bulbholder 2' is not provided with the rim H and recess 10. Instead an aperture 16 is provided and a bent over and curved part 17 of extension 14' is secured to the bulbholder 2' by means of a rivet 18 passing through aperture 16. The rivet 18 also serves to secure an earth return terminal 19 to the outside of the bulbholder. This enables an electrically insulating body to be used. Apart from these differences, the bulbholder of FIG. 2 is manufactured, and operates, in the same way as that described with reference to FIG. i.

What is claimed is:

l. A bulbholder comprising a tubular body open at both ends, opposed recesses and shoulders in said body for receiving, in bayonet fashion, a bulb when passed into said body via one of the open ends thereof, said tubular body being internally tapered inwardly towards said one of the open ends, a compression spring disposed in said body and arranged to urge said bulb, in use, against said shoulders, and an extension of said compression spring engaging the body so as to prevent said compression spring from passing through the other open end of said body.

2. A bulbholder as claimed in claim 1, wherein the body is formed integrally with a lamp reflector.

3. A bulbholder as claimed in claim 1, wherein said extension comprises an outwardly turned end portion of the spring adjacent the said other open end of the body, said outwardly turned end portion being engaged with the body adjacent said open end thereof.

4. A bulbholder as claimed in claim 3 wherein said end portion terminates in an outwardly directed hook, said turned back end portion extending from the end of the spring adjacent said other open end of the body in a direction towards said one open end so that the hook engages a rim of the body around said one end thereof.

5. A bulbholder as claimed in claim 3, wherein said end portion terminates in a portion which is secured to the body by securing means.

6. A bulbholder as claimed in claim 5, wherein said securing means is a rivet.

7. A bulbholder as claimed in claim 5, wherein the securing means also secures an electrical terminal to the exterior of the body. 

1. A bulbholder comprising a tubular body open at both ends, opposed recesses and shoulders in said body for receiving, in bayonet fashion, a bulb when passed into said body via one of the open ends thereof, said tubular body being internally tapered inwardly towards said one of the open ends, a compression spring disposed in said body and arranged to urge said bulb, in use, against said shoulders, and an extension of said compression spring engaging the body so as to prevent said compression spring from passing through the other open end of said body.
 2. A bulbholder as claimed in claim 1, wherein the body is formed integrally with a lamp reflector.
 3. A bulbholder as claimed in claim 1, wherein said extension comprises an outwardly turned end portion of the spring adjacent the said other open end of the body, said outwardly turned end portion being engaged with the body adjacent said open end thereof.
 4. A bulbholder as claimed in claim 3 wherein said end portion terminates in an outwardly directed hook, said turned back end portion extending from the end of the spring adjacent said other open end of the body in a direction towards said one open end so that the hook engages a rim of the body around said one end thereof.
 5. A bulbholder as claimed in claim 3, wherein said end portion terminates in a portion which is secured to the body by securing means.
 6. A bulbholder as claimed in claim 5, wherein said securing means is a rivet.
 7. A bulbholder as claimed in claim 5, wherein the securing means also secures an electrical terminal to the exterior of the body. 